Math lesson plan · 2nd grade (Year 3 in England) · 45 minutes
Story problems: work out the starting amount
Addition and subtraction
CCSS 2.OA.A.1England: Y2 Addition and subtractionEngland: Y3 Addition and subtraction
Objective and success criteria
Students will: Story problems: work out the starting amount.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: Story problems: find the missing change; Find the missing number in additions and subtractions to 100
Leads to: the next skill in this area.
Materials: Base-ten blocks, Number lines, Hundred square, Mini whiteboards and pens, Printed student sheet (below).
Warm-up · 5 min
- Quick retrieval from earlier learning (Story problems: find the missing change; Find the missing number in additions and subtractions to 100). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Fatima had 7 marbles. Ben gave Fatima some more. Now Fatima has 11. How many marbles did Ben give? → 4Prompt: 7 + ? = 11
- Fatima had 13 crayons. Fatima gave some to Mateo. Now Fatima has 9 left. How many crayons did Fatima give away? → 4Prompt: Fatima started with 13 and ended with 9.
- Liam had some beads. Then Liam got 3 more. Now Liam has 6. How many beads did Liam have at the start? → 3Prompt: ? + 3 = 6
Hook · 5 min
- Give a real shopping total or a score difference and ask for a quick estimate first.
- Share the objective: Story problems: work out the starting amount. Read the success criteria together.
I do: model it · 10 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: Noah had some photos. Then Noah got 12 more. Now Noah has 38. How many photos did Noah have at the start?
- Step 1: 38 − 12 = 26
- Step 2: 26
- Answer: 26
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 10 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- Kai had some crayons. Then Kai got 22 more. Now Kai has 38. How many crayons did Kai have at the start? → 16Prompt: ? + 22 = 38
- Liam had some shells. Liam gave 16 to Zara and has 24 left. How many shells did Liam have at the start? → 40Prompt: ? − 16 = 24
You do: independent practice · 10 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 5 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- Ava had 42 crayons. Tariq gave Ava some more. Now Ava has 79. How many crayons did Tariq give? → 37Prompt: 42 + ? = 79
- Ana had some marbles. Then Ana got 24 more. Now Ana has 39. How many marbles did Ana have at the start? → 15Prompt: ? + 24 = 39
Watch out for
- Subtracting the smaller digit from the bigger one in every column (52 − 17 = 45).
- Forgetting to add the regrouped (carried) ten.
Support and stretch
Support
- Review first: Story problems: find the missing change.
- Use concrete materials: base-ten blocks.
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/math/grade-2.
Free lesson plan from eurekami.com/lesson-plan-builder